Re: [x86/signal] 3aac3ebea0: will-it-scale.per_thread_ops -11.9% regression

[Thomas Gleixner]

On Tue, Dec 07 2021 at 18:49, Chang Seok Bae wrote:
> On Dec 7, 2021, at 05:38, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>> On Tue, Dec 07 2021 at 09:21, kernel test robot wrote:
>>> (please be noted we made some further analysis before reporting out,
>>> and thought it's likely the regression is related with the extra spinlock
>>> introducded by enalbling DYNAMIC_SIGFRAME. below is the full report.)
>>> 
>>> FYI, we noticed a -11.9% regression of will-it-scale.per_thread_ops due to commit:
>> 
>> Does that use sigaltstack() ?
>
> FWIW, I was also wondering about this with:
>
> $ git clone https://github.com/antonblanchard/will-it-scale.git
> $ cd will-it-scale/
> $ git grep sigaltstack
> $
>
> But, the test seems to use python via runtest.py. And the python code has
> sigaltstack():
>     https://github.com/python/cpython/blob/main/Modules/faulthandler.c#L454

But how does that affect the test written in C? Mysterious!